Pressure sensor semiconductor dies include a diaphragm for sensing pressure. The sensed pressure is converted to an electrical parameter such as change in resistivity. Pressure sensor dies are typically encased in a molding compound to protect the connections to the die and the die itself from corrosion and other adverse effects. Molding compounds typically have an elastic modulus of greater than 1 GPa at room temperature and therefore are relatively hard. Conventional molded pressure sensor packages have a window or cavity in the molding compound over the diaphragm of the pressure sensor die so that the diaphragm remains uncovered by the molding compound.
For pressure sensor applications, a mechanical coupling is provided between a molded pressure sensor package and a module housing such as a side air bag module for an automobile. A flexible seal is required to ensure a full and unrelenting pressure is redirected to the diaphragm of the pressure sensor die. The flexible seal should not exert any excessive force on the pressure sensor package and thus on the pressure sensor die, otherwise the electrical functionality of the pressure sensor die may be impaired. Conventionally, such a flexible seal is realized after the pressure sensor package is placed within the module housing e.g. such as the housing for a side air bag module. Significant effort is required by the module integrator to form a proper seal between a molded pressure sensor package and the module housing.